The Artefact

The Artefact, as it simply named, is a rocky construction of the Eridians, a piece of a Vault door for the purpose of channeling specific Infinite energy acutely for a variety of purposes.

Construction
The Artefact was created presumably around the same time as the Vault of the Dreamer was, as the panel where it was stored was built specifically below the arena the Dreamer to be accessed once the creature itself was defeated.

This was likely for the purpose so that the victor of the battle would be able to track other Vaults and destroy what as inside them. It is for this reason that it is likely there were limitations to the device that prevented it getting out of hand.

This did not stop Caine from an alternate timeline, however whether this future ever could have come to pass to begin with is questionable as the visions were merely created by Amelia as a form of prophecy to convince Matt to go after the Vault.

Functions
It could be used as a weapon, by directing beams of volatile energy towards a target, burning right through them in the process. In an alternate timeline, Caine used this to murder Matt and Gaige. In the current timeline, this ability was only used once by Matt, upon the Artefact itself. It was thrown across the Vault of the Dreamer by Caine and thought lost.

However, it turned out that it remained in its spot, protected by a forcefield. When Fiona touched it, it shocked her and she was unable to get past the shield of invisible Infinite energy. It remained reinforced until the combined efforts of Matt and Amelia were able to cancel out the energy signature and collect the relic inside.

It was when they collected the Artefact that they discovered another function - to present a map of Eridian constructions, like Vaults and Tombs, on Pandora, similar to that of the Vault Key. They used this to find the various Tombs on the planet.

Appearance
The Artefact appears to be a chunk of debris from a Vault door, glowing purple with Infinite energy with a slight silvery glint to it under certain lighting conditions. The rock is extremely dense, leaving no room for air within it and resulting in a very heavy mass, and this meant that both Matt and Amelia had to strain to hold on to it for too long. Its dimensions are unknown, but it is not too large to fit in Matt's hand, so it is likely just a bit bigger than the size of the average hand.

There are no visible interfaces on the relic, and it seems that its functions are only activated through thought alone, as shown when users were able to use the relic in the exact way they wanted to when they picked it up.